A Monte Carlo code for the simulation of heavy-ion tracks in water.

TILDA, a new Monte Carlo track structure code for ions in gaseous water that is valid for both high-LET (approximately 10(4) keV/microm) and low-LET ions, is presented. It is specially designed for a comparison of the patterns of energy deposited by a large range of ions. Low-LET ions are described in a perturbative frame, whereas heavy ions with a very high stopping power are treated using the Lindhard local density approximation and the Russek and Meli statistical method.

Breakup of H2 in singly ionizing collisions with fast protons: channel-selective low-energy electron spectra.

Dissociative as well as nondissociative single ionization of H2 by 6 MeV proton impact has been studied in a kinematically complete experiment by measuring the momentum vectors of the electron and the H+ fragment or the H+2 target ion, respectively. For the two ionization pathways, the electron spectra reveal the role of autoionization of the doubly and singly excited states of H2. The latter explicitly involve the coupling between the electronic and the nuclear motion of the molecule.

Interference effect in electron emission in heavy ion collisions with h2 detected by comparison with the measured electron spectrum from atomic hydrogen.

Direct evidence of the interference effect in the electron emission spectra from ionization of molecular hydrogen in collisions with bare C and F ions at relatively low collision energies is presented. Oscillations due to the interference are deduced by comparing the measured double differential cross sections of the electrons emitted from molecular hydrogen to those emitted from atomic hydrogen, rather than using the calculated cross sections for H as in a previous report. We believe these experimental data provide stronger support for the evidence of the interference effect.

Contribution from the inner shell of water vapour to dose profiles under proton and alpha particle irradiation.

Doubly differential cross sections for electron emission calculated using the CDW-EIS model and a simple approximation for the electron transport in the target are used to obtain dose profiles around the ion path for proton and alpha particles in water vapour. The contribution from each initial molecular orbital is determined. At large distances from the track, discrepancies are found with other models and with the well known r-2 dependence.

Theoretical calculation of electronic stopping power of water vapor by proton impact.

The energy loss of proton beams in water vapor is analyzed with a full quantum-mechanical treatment, the distorted-wave model. This model takes into account distortion effects due to the long-range Coulomb potential. Projectile energies from 10 keV up to 1 MeV are considered.